This invention relates to a method for detecting the existence of weak links in the current path of electrically continuous superconducting samples. The apparatus used in the method of the present invention is generally described in commonly assigned U.S. patent application Ser. No. 07/238,682 entitled "A Novel Technique for Detection of Superconductivity" filed Sept. 31, 1988 and incorporated herein by reference. The method of this invention is a variation of Ser. No. 238,682 in which the magnetically modulated electrical resistance response of the sample is phase detected and recorded as a function of temperature.